1. Field of the Invention
This invention relates to cryptographic communications in general and, more particularly, to methods and apparatus for private communications and remote authentication.
2.Description of the Related Art
Parties often wish to conduct private and authenticated communications. While privacy can be sought through physical means it is often more efficient and effective to employ cryptographic means. And while authentication can be sought through physically secure and dedicated facilities, it too can be accomplished more easily with cryptographic techniques.
In the prior art, this required that both parties to the communications kept a cryptographic key in their respective possession so as to be able to decrypt and/or authenticate the communications from the other party. When, for example, one of the parties is a computer system, it is inadvisable for the computer to store the cryptographic key either in clear form or in a reversibly-encrypted form. See R. H. Morris and K. Thompson, "UNIX Password Security," Communications of the ACM, Vol. 22, pp. 594 (Nov. 1979).